summaryrefslogtreecommitdiff
path: root/net/bridge/netfilter/ebt_arpreply.c
diff options
context:
space:
mode:
Diffstat (limited to 'net/bridge/netfilter/ebt_arpreply.c')
-rw-r--r--net/bridge/netfilter/ebt_arpreply.c97
1 files changed, 97 insertions, 0 deletions
diff --git a/net/bridge/netfilter/ebt_arpreply.c b/net/bridge/netfilter/ebt_arpreply.c
new file mode 100644
index 00000000000..b934de90f7c
--- /dev/null
+++ b/net/bridge/netfilter/ebt_arpreply.c
@@ -0,0 +1,97 @@
+/*
+ * ebt_arpreply
+ *
+ * Authors:
+ * Grzegorz Borowiak <grzes@gnu.univ.gda.pl>
+ * Bart De Schuymer <bdschuym@pandora.be>
+ *
+ * August, 2003
+ *
+ */
+
+#include <linux/netfilter_bridge/ebtables.h>
+#include <linux/netfilter_bridge/ebt_arpreply.h>
+#include <linux/if_arp.h>
+#include <net/arp.h>
+#include <linux/module.h>
+
+static int ebt_target_reply(struct sk_buff **pskb, unsigned int hooknr,
+ const struct net_device *in, const struct net_device *out,
+ const void *data, unsigned int datalen)
+{
+ struct ebt_arpreply_info *info = (struct ebt_arpreply_info *)data;
+ u32 _sip, *siptr, _dip, *diptr;
+ struct arphdr _ah, *ap;
+ unsigned char _sha[ETH_ALEN], *shp;
+ struct sk_buff *skb = *pskb;
+
+ ap = skb_header_pointer(skb, 0, sizeof(_ah), &_ah);
+ if (ap == NULL)
+ return EBT_DROP;
+
+ if (ap->ar_op != htons(ARPOP_REQUEST) ||
+ ap->ar_hln != ETH_ALEN ||
+ ap->ar_pro != htons(ETH_P_IP) ||
+ ap->ar_pln != 4)
+ return EBT_CONTINUE;
+
+ shp = skb_header_pointer(skb, sizeof(_ah), ETH_ALEN, &_sha);
+ if (shp == NULL)
+ return EBT_DROP;
+
+ siptr = skb_header_pointer(skb, sizeof(_ah) + ETH_ALEN,
+ sizeof(_sip), &_sip);
+ if (siptr == NULL)
+ return EBT_DROP;
+
+ diptr = skb_header_pointer(skb,
+ sizeof(_ah) + 2 * ETH_ALEN + sizeof(_sip),
+ sizeof(_dip), &_dip);
+ if (diptr == NULL)
+ return EBT_DROP;
+
+ arp_send(ARPOP_REPLY, ETH_P_ARP, *siptr, (struct net_device *)in,
+ *diptr, shp, info->mac, shp);
+
+ return info->target;
+}
+
+static int ebt_target_reply_check(const char *tablename, unsigned int hookmask,
+ const struct ebt_entry *e, void *data, unsigned int datalen)
+{
+ struct ebt_arpreply_info *info = (struct ebt_arpreply_info *)data;
+
+ if (datalen != EBT_ALIGN(sizeof(struct ebt_arpreply_info)))
+ return -EINVAL;
+ if (BASE_CHAIN && info->target == EBT_RETURN)
+ return -EINVAL;
+ if (e->ethproto != htons(ETH_P_ARP) ||
+ e->invflags & EBT_IPROTO)
+ return -EINVAL;
+ CLEAR_BASE_CHAIN_BIT;
+ if (strcmp(tablename, "nat") || hookmask & ~(1 << NF_BR_PRE_ROUTING))
+ return -EINVAL;
+ return 0;
+}
+
+static struct ebt_target reply_target =
+{
+ .name = EBT_ARPREPLY_TARGET,
+ .target = ebt_target_reply,
+ .check = ebt_target_reply_check,
+ .me = THIS_MODULE,
+};
+
+static int __init init(void)
+{
+ return ebt_register_target(&reply_target);
+}
+
+static void __exit fini(void)
+{
+ ebt_unregister_target(&reply_target);
+}
+
+module_init(init);
+module_exit(fini);
+MODULE_LICENSE("GPL");